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Biomedical subjects

Andrew M Wo

Publications and source records attributed to Andrew M Wo.

3 recordsLinked to original sources

Microcontact printing of laminin on oxygen plasma activated substrates for the alignment and growth of Schwann cells.

Microenvironment mimicking biological situation is a vital issue in tissue regeneration. With much progress being made, one of the major challenges remains to develop a convenient method to fabricate the scaffold microenvironment suitable for cell attachment and proliferation. This article demonstrates the efficacy of microcontact printed laminin, an extracellular matrix protein, on three different oxygen plasma treatment substrates-tissue culture polystyrene, poly(methyl methacrylate) films, and chitosan films-for alignment and growth of the Schwann cells in in vitro culturing. Replica molding of polydimethylsiloxane elastomeric stamps, fabricated from patterned SU-8 structure on silicon master, was used to print laminin on the three substrates. Pattern and growth of Schwann cells for low (10(3) cells/cm(2)) and increased cell density (2 x 10(4) cells/cm(2)) on the varied substrates with and without microcontact printed laminin were characterized. Results of in vitro cell culture of Schwann cells showed a high degree of cell orientation on the laminin-micropatterned substrates for both cell densities. However, different cell seeding densities will strongly impact the morphology and orientation of Schwann cells. Microcontact printing proves to be a convenient means to pattern cell-recognition molecules on scaffold for cell-guilded growth in tissue regeneration.

Animals↗

Three dimensional electrode array for cell lysis via electroporation.

Microfabricated devices for cell lysis have demonstrated many advantages over conventional approaches. Among various design of microdevices that employ electroporation for cytolysis, most utilize Ag/AgCl wires or 2D planar electrodes. Although, simple in fabrication the electric field generated by 2D electrodes decays exponentially, resulting in rather non-uniform forcing on the cell membrane. This paper investigates the effect of electric field generated by 3D cylindrical electrodes to perform cell lysis via electroporation in a microfluidic platform, and compared with that by 2D design. Computational results of the electric field for both 2D and 3D electrode geometries showed that the 3D configuration demonstrated a significantly higher effective volume ratio-volume which electric field is sufficient for cell lysis to that of net throughflow volume. Hence, the efficacy of performing cell lysis is substantially greater for cells passing through 3D than 2D electrodes. Experimentally, simultaneous multi-pores were observed on leukocytes lysed with 3D electrodes, which is indicative of enhanced uniformity of the electric field generated by 3D design. Additionally, a single row of 3D electrode demonstrated a substantially higher lysing percentage (30%) than that of 2D (8%) under that same flow condition. This work should aid in the design of electrodes in performing cell lysis via electroporation.

Cell Culture Techniques↗

Thermal modeling and performance analysis of a thermoacoustic refrigerator.

A heat-driven thermoacoustic refrigerator has been designed and tested. A detailed thermal model of the device is presented. Energy balances within the system are discussed using external, heat exchanger, and stack control volumes in order to clarify the relationships of work and heat fluxes below and above onset. Thermal modeling is discussed as a tool for performance analysis as well as for determining system heat losses and finding input heat flows required by a thermoacoustic code. A method of using the control volume balance equations to find stack work and device efficiencies is presented. Experimental measurements are compared to DELTAE thermoacoustic modeling predictions. Modeling results show that viscous losses within the system have a significant impact on the device performance as well as on the ability of DELTAE to accurately predict performance. Modeling has led to an understanding of system performance and highlighted loss sources that are areas for improvement in a redesign.

Acoustics↗